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Finding the Fourth Proportional to 820.90, 1,132.87 and 489.36

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Solution

The fourth proportional to 820.90, 1,132.87 and 489.36 is: 675.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.90 : 1,132.87 = 489.36 : x
  2. Step 2: Convert to fraction form
    820.90/1,132.87 = 489.36/x
  3. Step 3: Cross multiply
    820.90x = 1,132.87 × 489.36
  4. Step 4: Simplify right side
    820.90x = 554,381.26
  5. Step 5: Solve for x
    x = 554,381.26/820.90
  6. Step 6: Final answer
    x = 675.33

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.